In some content delivery systems, such as video-on-demand systems, devices may be grouped into a plurality of service groups. Each service group may have a shared pool of bandwidth resources for content delivered to the service group. When an item of video-on-demand content is delivered to a device, the item may be provided to all of the devices in the service group of the device. Where multiple devices in the same service group request the same item of content, however, the item may be re-sent for each of the requesting devices in parallel, using a significant amount of network resources. These and other shortcomings are address in this disclosure.